The invention relates generally to outdoor lighting systems that provide lighting for roadways, parking lots, building exteriors, and other outdoor areas using fixtures mounted on poles or other structures. The lighting fixtures are wired to a source of alternating current (AC) line power and include drivers or ballasts providing power to lamps, light emitting diodes (LEDs) or other light sources. Improved energy efficiency is desired for outdoor lighting systems, and hence improved lighting fixtures and accessories are desired to provide communications capabilities by which outdoor lighting fixtures can be intelligently used to provide lighting without consuming excessive energy.
Wireless, non-optical radio frequency (RF) communications have been suggested for many industrial applications including street lighting. Mesh communications have enjoyed extensive advocacy. Message routing protocols that select from a plurality of possibilities for message routing can take advantage of having more than one node in communication with any other particular node within the mesh. This topology appears to offer redundancy and graceful degradation under node failures. Wireless non-optical RF communication links are, however; vulnerable to several problems including changing propagation environments due to construction, vehicle movements, and other time-varying communication path impairments. The wireless non-optical RF communication links are also susceptible to degradation due to changing electromagnetic noise characteristic and also potential malicious interference. Such changing environmental aspects may increase the latency of the communications transported on the mesh network, decrease its usable bandwidth, and concomitantly reduce its throughput. Additionally, operational problems with wireless non-optical RF mesh networks have been reported including maintenance and management complexities and difficulties, antenna design and successful operation under real-world conditions including implementation and maintenance issues, protocol problems and discovered deficiencies under scaling and unanticipated interference scenarios.
While a mesh communications architecture functions well in fulfilling some luminaire communications, there are segments of luminaire communications that may require protection against some of the occasional impairments experienced in a wireless mesh architecture. There is therefore a need for other communication and control network options for operating and monitoring assets within a street lighting network.